Gall bladder bile lipid composition, bile acid composition, bile acid pool size and turnover rates were measured in 6 normal humans before and during a 4-6 day fast. One subject admitted for this project was found to have endometrial carcinoma and had biliary lipid studies before and after bilateral oophorectomy. Also, bile acid pool sizes measured in a group of 52 normal subjects studied under baseline conditions in this and several related projects were analyzed in relationship to sex, body size and bile saturation.